a) Field of the Invention
The present invention relates to an assembly and method of plural conductive slots sharing an overheating destructive fixing element, and more particularly to an assembly and method of plural conductive slots sharing an overheating destructive fixing element, such that when any one conductive slot reaches each own limiting working temperature respectively, the overheating destructive fixing element is destructed by reaching a pre-determined temperature.
b) Description of the Prior Art
To prevent a circuit from issues of current overload, short circuit and overheating, a fuse or an overload protector is usually provided at the circuit. When the temperature of the circuit gets too high or the current gets too large, the fuse affected by the high temperature becomes blown or a bi-metal shrapnel of the overload protector becomes disengaged, so as to cause the circuit become open circuit and turned off to ensure electricity safety.
Regarding the prior art of a fuse structure, for example, the Taiwan Patent No. I371053 discloses a “Thermal Fuse Connecting Structure,” which mainly includes two terminals and a meltable metal engaged at the two terminals. In the event of current overload, circuit overheating or an excessively high ambient temperature, the meltable metal is heated to cause a rise in the temperature and becomes molten and broken. As such, the two terminals become disconnected and the circuit then becomes a turn-off state.
However, the patent I371053 at least exists with following shortcomings, including that:                (1) Except for a few metallic elements, such as bismuth, tin, indium and alkali metal, the melting point of most metals is above 300° C.; for example, the melting point is 1084.6° C. for copper and 1535° C. for iron. In the abovementioned patent I371053, if a metal with the melting point below 300° C. is chosen as the meltable metal, then the bonding strength may not be strong enough that the two terminals cannot be combined stably. In addition, even the bonding strength is strong enough, the price of the meltable metal may be too high.        (2) As the meltable metal is a conductive material, when the meltable metal is molten and broken, if a residue of the meltable metal is stuck on the two terminals, the residue can easily cause miss contact between the two terminals that the circuit cannot be turned off completely. Or, the molten and broken meltable metal can be ejected off by the two terminals that are opened to turn off the circuit, hitting other objects to form miss contact, which results in short circuit. Therefore, it is still dangerous in using the connection structure.        
In addition, the U.S. Pat. No. 9,257,798 discloses a “Socket Having Overheating Destructive Limiting Element,” wherein every socket can use an insulative limiting element to form an open path. When the temperature of one socket gets too high, the limiting element thereof will be destructed and broken, such that the overheated socket becomes a turn-off state as the conductive plates are opened with respect to each other.
However, in the U.S. Pat. No. 9,257,798, every socket should be installed with a limiting element and thus every socket should be provided with a structure for installing the limiting element. Therefore, the entire volume of the socket cannot be reduced further, and the structure of the socket will be more complex that it is not easy to decrease the fabrication cost.
Furthermore, the Taiwan Utility Model Patent No. M433670 discloses an “Assembly Structure of an Extension Cord Socket with an Overload Protection Switch from Inside to Outside,” which includes a rocker-type overload protection switch. The detailed structure of the overload protection switch is disclosed in the Taiwan Utility Model Patent Publication Nos. 540811, 367091, 320335, 262168 and 208384. The overload protection switch is connected electrically with plural electrode plates which are all formed with plural slots. The rocker-type overload protection switch described above becomes a turn-off state when the temperature gets too high by current overload.
However, in the patent M433670, the distance between each slot and the overload protection switch is not the same. Therefore, upon practically using the patent, certain temperature difference exists between each slot and the overload protection switch under the distance effect of heat transfer, and the longer the distance between the slot and the overload protection switch, the larger the temperature difference. Accordingly, when the temperature of a slot at a far end gets too high, the overload protection switch will not be able to operate in time easily to turn off the circuit, which is still not safe enough in using the patent.